1. Field of the Invention
The present invention relates to sports shoes that have shock-absorbing soles.
2. Description of Background and Relevant Information
In many sports, the human body and, more particularly, the lower limbs, are subjected to substantial forces. A typical example of substantial forces to which the lower limbs are subjected occurs during jump landings. As the athlete touches the ground, his/her feet are subjected to a reaction of the ground that is as substantial as the jump is high. The human foot has a fleshy zone beneath the heel, whose role is to absorb the impacts to which the heel is subjected. This natural shock absorption is insufficient, and it is known to equip the shoes, especially sports shoes, with shock-absorbing devices.
In certain sports, such as skateboarding, jumps sometimes have ranges of several meters and the landings are generally performed on a hard and flat ground. Moreover, it is not advisable to provide a substantial shock absorption in the area of the board and trucks, because it is due to their rigidity that certain figures are possible. Consequently, the problem of shock-absorbing soles for the skateboard shoes has a different scope than that of more conventional sports shoes. Nevertheless, in a sport such as skateboarding, some of the movements are acrobatic and the rider must remain in constant contact with his/her environment. In particular, the feet, which rest on the board most of the time, must precisely inform the rider about his/her position in relation to the board and in space. This is why the sole of a sports shoe, such as a skateboard shoe, not only must absorb the impacts, but it must also transmit a certain amount of information to the rider, such as his/her position in space, including, for example, his/her position on the board.
The invention relates more particularly to skateboard shoes, and an object of the invention, among other things, is to enable a progressive and channeled shock absorption during landing from high and low jumps.
Furthermore, an additional object of the invention is to provide an increased sensation in the metatarsophalangeal bending zone, while preserving the shock absorption functions of a conventional product.
The object of the invention is achieved in that the intermediary sole is constructed of a plurality of parts and includes shock-absorbing structures that are only partially linked to one another, such that a relative movement of these shock-absorbing structures in the vertical direction, in relation to the intermediary sole, on the one hand, and in relation to one another, on the other hand, is possible.
In one of the embodiments of the invention, the shock-absorbing structures are cylindrical studs that are adapted to have a vertical movement with respect to one another.
In one embodiment of the invention, the shock-absorbing structures are cylindrical studs whose axis is vertical, or substantially vertical. These studs are not completely independent from one another but are partially connected, at only one portion of their lateral surface, to the intermediary sole. The studs are then constituted by an upper protuberance, a lower protuberance, and a central portion which connects the upper and lower protuberances to one another, on the one hand, and the studs to one another, on the other hand. The portion of the intermediary sole that connects the studs to one another by their central portion is called the core and is thin in order to facilitate the movement of the studs with respect to one another.
In another embodiment of the invention, the intermediary sole is made of a plurality of parts and includes two half-soles, or partial-soles: the lower, or bottom, intermediary half-sole, which is commonly referred to as the cup, and the upper, or top, intermediary half-sole, also called the insert. In this embodiment, the shock-absorbing structures of the intermediary sole include cylindrical studs, each of the latter being constituted by an upper protuberance connected by its base to the upper surface of the insert and by a lower protuberance connected by its base to the bottom surface of the cup. Such studs are arranged in the entire front zone, and more particularly in the metatarsophalangeal bending zone. These studs have a certain freedom of movement with respect to one another, and with respect to the remainder of the intermediary sole. The upper half-sole, or insert, therefore includes, in the metatarsophalangeal zone, an upper half-core from which upper protuberances project, whereas the lower half-sole includes a lower half-core from which lower protuberances project downward. When the two half-soles are assembled, each upper protuberance is aligned with a lower protuberance, thus defining the juxtaposed studs and having a certain vertical and rotational freedom of movement with respect to one another. Thus, the more precise and greater number of sensations are transmitted to the athlete from the surface on which he/she moves. Moreover, the material of the upper intermediary half-sole is less dense than the material of the lower half-sole so that shock absorption is progressive, and that comfort is ensured during walking and when performing low jumps, on the one hand, and landing from jumps several meters high, on the other hand.
An object of the invention is also achieved in that the intermediary sole includes two portions, each of which is made of a different material. Preferably, one of the materials is less dense than the other. The upper intermediary half-sole further includes a conical shape whose apex is oriented downwardly. This shape is nested in the bottom intermediary half-sole, which includes a complementary concave shape. Furthermore, this concave shape is extended by a vertical well. Thus, under the effect of an impact, the softer material of the upper intermediary half-sole is channeled by the walls of the concave shape until it can flow out of this shape by the vertical well connected to the bottom of the latter.
Preferably, the difference in density between the material of the upper intermediary half-sole and that of the lower intermediary half-sole is such that during landing from a high jump, the compression of the lower intermediary half-sole begins to occur before that of the upper intermediary half-sole reaches its limits. The density of the upper intermediary half-sole is selected such that the shoe is comfortable during normal use, and that shock absorption is ensured during walking and low jumps; this material is relatively flexible. The material of the lower intermediary half-sole is more rigid so as to ensure shock absorption even when landing from a jump several meters high.